Rear End Id, Tranny Id?

[Rc 415]

My truck is a 1983 Chevy Scottsdale Stepside, the person I bought it from said that the motor is a newer 350 crate with about 5k miles on it, does it look like a crate engine? I need to find out what kind of read end/the gear ratio I have in this truck, can anyone tell? and the tranny, I'm thinking TH-700, am I correct? Its automatic.

[Srubydo1986]

i think it a 700r4 caus of the square pan for the rear ration i dont know what the code mean but i think it might be on the driver door two

[cliffsta]

The options code indicated a TH700R4... the sticker on the side of the motor tells me it is indeed a crate motor (unless he's REALLY a crook and slapped that sticker on the side of the motor ), the rear-end is a GM 10-bolt, not sure of the ratio (my glove box sticker said mine has 2.56.. not sure what the "standard" ratio is). Might check www.73-87.com he might have that code on his site or a link to a code reading site.

Hope that helped.

[Rc 415]

Originally Posted by cliffsta

The options code indicated a TH700R4... the sticker on the side of the motor tells me it is indeed a crate motor (unless he's REALLY a crook and slapped that sticker on the side of the motor ), the rear-end is a GM 10-bolt, not sure of the ratio (my glove box sticker said mine has 2.56.. not sure what the "standard" ratio is). Might check www.73-87.com he might have that code on his site or a link to a code reading site.

Hope that helped.

LOL, I just realized that about the transmission, I was too busy looking at the code for the gear ratio that I didnt notice the tranny part! I have more pics of the motor, and I believe that it is indeed a crate goodwrench, I need to find out more about it though, because the stock was a 5.0 liter, and those were usually 305's right?

[Rc 415]

Originally Posted by Srubydo1986

i think it a 700r4 caus of the square pan for the rear ration i dont know what the code mean but i think it might be on the driver door two

Thanks, I'll check the door tomorow!

[cliffsta]

Yes, the 5.0 is 305 cubic inches, 350 is 5.7. Its ok, my dad didn't know my truck had caution flashers and he bought it new in 1980...

[84 400]

It looks to be the base stick replacement 350 5.7 liter. i think it is a 290 hp??? It definatly looks to be a crate judging by the sticers but it does look kinda dirty to have 5,000. Then again every body cleans diffrent things. 10 bolt rear with 700r4 od trans. Wish i could help on the rear ratio

[Rc 415]

Thanks guys now all i gotta do is figure out the gear ratio!

[swervin ervin]

If you will look on the passenger side axle tube, about 3 - 6 inches out from the center section on the front side, there will be a 3 letter/number code, hand die punched into the tube. You will need to clean it real good because they are extremely hard to find being as they are only around 1/8" tall. Find this code and I will tell you what ratio your truck came stock with.

[Rc 415]

[Slonaker]

The sticker on your engine looks just like the one on my crate engine. I would say it probably is one unless the PO just used the valve covers off of one. Mine is the 260 hp cheapo crate engine, but the 290 hp 350 probably uses the same stickers.

Slonaker

[Rc 415]

I'm pretty confident that its a crate, here are a few other crappy pics:

[Rc 415]

While we are on the subect of the engine, I want to get a dress up kit, specifically this one:
http://www.jegs.com/webapp/wcs/store...59725_-1_11357
but I am wondering what would happen to the hoses and stuff that plugs into the current air cleaner? Also that aluminum flex hose you see coming form the manifold to the air cleaner?

[cliffsta]

All that stuff is emissions and can be eliminated / relocated (unless your local area inspects emissions items closely). Your kit there includes the breather cap for the valve cover, which eliminates the crank case breather hose that plugs into the air cleaner. Another one of those hoses is for the vacuum switch in the air cleaner, so it will be eliminated if you went with an aftermarket air cleaner such as the one in that kit. That alluminum hose is the pre-heater hose, warms the air going into the carburetor to help cold weather warmup. You can do without it.

Hope that helps.

[86k10]

From what I remember, rear axle standard is a 2.73, way to high geared for the 700.

[84slopwaggin]

What about it being a 3.08? I just removed the smog crap off my engine. Boy did it wake the motor up. I'm happy we have no smog police, as of now. Headers next fellas.

[Rc 415]

thanks guys!

[swervin ervin]

TUM is a 2.73 ratio. Standard rear axle only means what GM considered standard for each year, or something close to that anyway. Somebody explained this before in great detail. I just can't remember who it was. 2.73 was standard in 85 also.

On another subject, have you thought about reducing the size of your photos. A lot of folks on here are on dialup and it kills them to open threads like this one.

[Rc 415]

Hey sorry about the pics, I'll resize them for forums when I get home!

[Rc 415]

Originally Posted by 86k10

From what I remember, rear axle standard is a 2.73, way to high geared for the 700.

But they are both stock right? Why would Gm do that?

[Captkaos]

Originally Posted by swervin ervin

TUM is a 2.73 ratio. Standard rear axle only means what GM considered standard for each year, or something close to that anyway. Somebody explained this before in great detail. I just can't remember who it was. 2.73 was standard in 85 also.

I believe it was 73-87 Dictionary KIILew. I forgot you had the axle codes Mike...

[swervin ervin]

Yeah, my 85 came stock with 2.73 gears and a 700-R4 tranny. 86k10 is correct, the gears are way too high for an overdrive tranny. I have 3.73 gears in mine now and I'm way happier.

As for why GM does stuff, who knows. They sure don't have any logical reason I can think of. It was a gas mileage reason I'm guessing but what they didn't take into consideration is overdrive. With the high gears it would always unlock and drop down into a lower gear, especially going up hills. A lower rear gear would keep it locked into overdrive and thus save on gas in the long run.

[swervin ervin]

You're right Chis, it was Ken, our 73-87 know it all.

Yes, I've got the numbers for all the years.